Diffusion coefficients of aromatics in nonporous PEBA membranes

Diffusion coefficients of the aromatic compounds phenol, aniline, 2-chlorop henol, 4-nitrophenol, 2,4-dinitrophenol, 4,4'-isopropylidenediphenol (Bisph enol A) and pyridine in dense polyether-polyamide block-copolymer (PEBA) 40 33-PE and PEBA 4033 membranes have been measured using the technique of the time-dependent dialysis in dilute aqueous solution. A new evaluation proce dure is presented which allows to determine diffusion coefficients in case of an nonstationary dialysis process. Diffusion coefficients obtained at 29 8.15 and 323.15 K are used to determine the so called activation energy of diffusion. The data are obtained in membranes used under realistic conditio ns of pervaporation or reverse osmosis where the polymer membrane is satura ted to ca. 1% with water. The method is generally useful for estimating par ameters of membrane separation processes in a quantitative way based on the solution diffusion model. (C) 2000 Elsevier Science B.V. All rights reserv ed.